Mechanical timepiece comprising a tourbillon

ABSTRACT

The invention relates to a timepiece consisting of a main plate ( 24 ) having the following components mounted thereto: a time base which is formed by a tourbillon ( 16 ) comprising a rotatable frame, which appears in an opening ( 14   a ) in the dial ( 14 ) thereof; and time information display means which are controlled from the time base. The aforementioned display means comprise a rotatable ring ( 40 ) which appears in the opening ( 14   a ) in the dial, co-axially around the frame, and ring drive means.

The present invention relates to a mechanical timepiece provided with atourbillon.

It is known that, when the escapement of a mechanical watch is in thevertical position, the Earth's gravitation accelerates or, on thecontrary, brakes the oscillation of its balance, causing it either to befast or slow. In order to compensate for these deviations in the runningrate, Abraham-Louis Breguet proposed, in 1801, an exceptional regulatingmember, the tourbillon with which high-quality watches are now equipped.

In a tourbillon, a movable frame is driven by the barrel, through thetrain, at a rate of one revolution per minute. At its center, this framecarries the sprung balance. The escape wheel is driven by a pinionoff-centered with respect to the axis of the frame, and called thesatellite pinion, which meshes with a fixed wheel. By rotating, theframe thus cancels out the deviations in the running rate of the watch.

Watchmakers have always sought to show the elegant and prestigiousmechanism constituted by the tourbillon on the dial side, furnished atthis location with an appropriate opening. This choice making thedisplaying of the date by a disk in an aperture difficult, thetourbillon-type watches proposed hitherto generally comprise a datedisplay with the aid of a small hand which, from an aesthetic point ofview, competes with the tourbillon, or then occupies room which could beassigned to the displaying of higher-quality functions (power reserve,equation of time, temperature, chronograph, etc). It is, moreover,difficult to read the date of the month when it is displayed by means ofa hand, as is the case for the “automatic tourbillon with perpetualcalendar” watch marketed by the firm Blancpain.

The Audemars Piguet company has developed a watch, called “TourbillonGrande Date Jules Audemars”, which is equipped with a date display in anaperture. The solution adopted involves display by means of two disks,one for the tens, the other for the units, this requiring considerableenergy and occupying a large area of the dial, preventing the display ofother information.

The two aforementioned watches are described, for example, in themagazine “Classe Evasion” No 6, March 2001, published by the AGEFI(Switzerland).

An aim of the present invention is to propose a timepiece withtourbillon which can provide an indication of the date, or of any othervalue desired by the maker, without occupying, on the dial, too muchroom impeding the tourbillon or taking the place of more prestigiousfunctions.

More precisely, the invention relates to a timepiece of the typecomprising a main plate and, mounted on the latter, a time base formedby a tourbillon comprising a rotatable frame which appears in an openingmade in its dial, and time information display means controlled from thetime base. This timepiece is mainly characterized in that said displaymeans comprise a rotatable ring which appears in the opening of the dialaround the frame of the tourbillon, coaxially with it, and membersdriving this ring.

The timepiece according to the invention also comprises the followingmain characteristics:

-   -   the frame of the tourbillon is mounted rotatably between the        main plate and an additional plate;    -   this plate comprises cutouts through which the tourbillon        appears;    -   the display ring is mounted rotatably inside a groove made in        the additional plate;    -   this ring is associated with a toothed wheel which is concentric        with it and co-operates with the driving means;    -   this toothed wheel also co-operates with means of manual        adjustment of the position of the display ring;    -   the ring is held in place by at least one platelet fixed to the        additional plate and protruding into its groove so as to fit        between the ring and its toothed wheel; and    -   the display ring is a date indicator.

Other characteristics of the invention will emerge from the descriptionwhich follows, given in conjunction with the appended drawing, in which:

FIGS. 1 and 2 represent, viewed from above in perspective, a part of thetimepiece according to the invention, respectively with and without itsdial; and

FIGS. 3, 4 and 5 are sectional views, respectively along III—III, IV—IVand V—V, of a part of the movement intended to equip this timepiece.

The timepiece illustrated in FIGS. 1 and 2 is intended to display thehour, the minute, the second and the date. It comprises, for thispurpose, a base movement 10 and an additional plate 12, fixed on thebase movement 10 and intended to carry certain components, as will beexplained in greater detail with reference to FIGS. 3 to 5. A dial 14,fixed on the base movement 10 and provided with a circular opening 14 a,serves as reference for the display of the time information.

The running rate of this timepiece is regulated by a tourbillon 16,visible through the opening 14 a and mounted pivotably on the basemovement 10 and the plate 12. The tourbillon 16 comprises a pipe 18intended to carry a seconds hand.

The hour and the minute are displayed, in a conventional manner, bymeans of hands that do not appear in the drawing, carried respectivelyby coaxial runners 20 and 22 disposed at the center of the movement 10.

The movement 10 comprises a framework, formed by a main plate 24 and bybridges that are not visible in the drawing. This framework serves assupport to the movable elements of the movement 10, more particularlyand in a conventional manner, to the barrel, to the finishing train andto the time setting mechanism.

If the watch is an automatic one, the framework may, furthermore, carrythe automatic winding mechanism.

The additional plate 12 makes it possible to add mechanisms undertakingcomplementary functions, in this instance a date display. It exhibits aprotuberance 26 sitting in the opening 14 a of the dial. This plate isfixed and positioned on the main plate 14 by means that are notrepresented, for example feet and screws, and on which are disposed themembers of the complementary mechanisms.

As shown in FIG. 3, the tourbillon 16 comprises a frame 28, mountedpivotably about an axis A—A, on the one hand, on a bridge integral withthe main plate 24 and, on the other hand, on the plate 12.

On the dial side, the frame carries a seat 30 carrying the pipe 18. Theprotuberance 26 is drilled with a hole into which is hammered a jewel 32serving as bearing for the pipe 18. In a conventional manner, a sprungbalance 34 is mounted in the frame 28, pivoting about the same axis A—A.

The protuberance 26 of the additional plate 12 possesses, around thejewel 32, cutouts 36 (visible in FIGS. 1 and 2) making it possible tosee the tourbillon 16. The plate 12 furthermore comprises an annulargroove 38, with axis A—A, open on the dial side and serving as housingfor a date ring 40 which bears the numerals 1 to 31. This ring 40possesses, inwardly, an annulus 42 onto which is hammered a crown 44with thity-one teeth appearing in the opening 14 a of the dial.

As shown in FIGS. 2 and 3, a central wheel 48, driven at a rate of onerevolution in twelve hours, meshes with an intermediate wheel 50 whichitself meshes with a control wheel 52 associated with a spring 54terminating in a drive pawl 56 co-operating with the crown 44. Thewheels 50 and 52 make one revolution per day.

Thus, a date mechanism of conventional type is produced, by virtue ofwhich, each day at midnight, the pawl 56, propelled by the spring 54which is previously stretched, advances the crown 44 by one step andhence likewise the date ring 40 surrounding the tourbillon 16.

Reference will now be made, more particularly, to FIGS. 2 to 4 whichshow the way in which the ring 40 is set to the correct date. A wheel 58is linked, in a conventional manner, with the train for manually settingthe watch to time by means of a control stem. This wheel meshes with arunner 60, furnished with six leaves co-operating with the crown 44.

By virtue of this construction, turning the wheel 58 with the aid of thecontrol stem allows the runner 60 to rotate the date ring 40 so as toset it into the position where it displays the date desired by the user.

Finally, reference will be made to FIGS. 2 and 5 in which appear,disposed substantially at 120° to one another, toward the outside of thetimepiece, two platelets 62 fixed by a screw 64 onto the plate 12. Eachplatelet protrudes, via its end, into the groove 38 so as to fit betweenthe date ring 40 and its crown 44, which it thus holds in place.

The present description has been given while referring to a tourbillonsurrounded by a date-indicating ring. It goes without saying, however,that the invention is not limited to the displaying of the date and thatthe ring may serve as indicator for any other time information, themanagement of which is well understood by the maker.

Thus, proposed is a timepiece with tourbillon which can provide anindication of the date, or of any other value desired by the craftsman,without occupying, on the dial, too much room.

1. A timepiece comprising a main plate (24) and, mounted on the latter,a time base formed by a tourbillon (16) comprising a rotatable frame(28) which appears in an opening (14 a) made in a dial of the timepiece(14), and time information display means controlled from said time base,characterized in that said means comprise a rotatable ring (40) whichappears in said opening around said frame (28), coaxially with it, andelements driving this ring.
 2. The timepiece as claimed in claim 1,characterized in that said frame (28) is mounted rotatably between saidmain plate (24) and an additional plate (12).
 3. The timepiece asclaimed in claim 2, characterized in that said plate (12) comprisescutouts (36) through which the tourbillon (16) appears.
 4. The timepieceas claimed in claim 3, characterized in that said ring (40) is mountedrotatably inside a groove (38) made in said plate (12).
 5. The timepieceas claimed in claim 4, characterized in that said ring (40) isassociated with a toothed wheel (44) which is concentric with it andco-operates with said driving means.
 6. The timepiece as claimed inclaim 5, characterized in that said toothed wheel (44) also co-operateswith means of manual adjustment of the position of said ring.
 7. Thetimepiece as claimed in claim 5, characterized in that said ring (40) isheld in place by at least one platelet (62) fixed to said plate (12) andprotruding into said groove (38) so as to fit between said ring (40) andsaid toothed wheel (44).
 8. The timepiece as claimed in claim 1,characterized in that said ring (40) is a date indicator.
 9. Thetimepiece as claimed in claim 2, characterized in that said ring (40) isa date indicator.
 10. The timepiece as claimed in claim 3, characterizedin that said ring (40) is a date indicator.
 11. The timepiece as claimedin claim 4, characterized in that said ring (40) is a date indicator.12. The timepiece as claimed in claim 5, characterized in that said ring(40) is a date indicator.
 13. The timepiece as claimed in claim 6,characterized in that said ring (40) is a date indicator.
 14. Thetimepiece as claimed in claim 7, characterized in that said ring (40) isa date indicator.